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Donald Dingwell: "Magma to Tephra: Ash in the Earth System"

Experimental Volcanology, LMU

Academic Year 2018/2019

The investigation of volcanic activity at the surface of our Earth demands an inherently interdisciplinary scientific approach – from geophysics and fluid mechanics, to atmospheric chemistry, biochemistry, material and social science.

To provide a scientific synthesis of shallow volcanic systems, the research group of Prof. Dr. Donald Dingwell divides the shallow and surface volcanic system into three fundamental physical components:

The upper parts of a volcanic plumbing system are permeable to through-flowing volatile acid gases and thus, the magma itself acts a physico-chemical filter, reacting and altering with time, growing and dissolving crystals and glass, and corroding the liquid phase in a complex cocktail of reactivity.

During eruption the magma undergoes a material transition from a coherent mass to volcanic ash in a dusty gas, increasing the surface area available for reactions by orders of magnitude.

And as ash is transported through an initially hot, and dynamically cooling plume of those same acid gases, it continues to react. In this latter phase, ash can take up significant proportions of biologically relevant elements, effectively storing them on the ash surface ready for release into the biosphere when the ash is deposited.

In the above framework, the research Group tracks the complex reactions between magma and volatile gases over the full lifecycle of ash from source to sink – that is, from eruption in the lithosphere through to incorporation in our bio- and anthroposphere.